A multicomponent equimolar proton-conducting quadruple hexagonal perovskite-related oxide system

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• High configurational entropy concept drives structural stability in multicomponent oxides.
• Existing systems often limited to fewer than 3 distinct cation sites.
• Need for novel oxide systems with enhanced properties.

Purpose of the Study:

• To synthesize and characterize a novel multicomponent equimolar proton-conducting oxide system.
• To investigate the impact of increasing configurational entropy on chemical stability and proton conductivity.
• To expand the application of multicomponent models to new crystal structures.

Main Methods:

• Atomic-scale imaging using scanning transmission electron microscopy (STEM).
• AC-impedance spectroscopy for conductivity analysis.
• Synthesis of Ba5RE2Al2ZrO13 (RE = rare earth elements) systems with varying rare earth elements.

Main Results:

• Successfully synthesized a quadruple hexagonal perovskite-related oxide system (Ba5RE2Al2ZrO13) with up to eight different rare earth elements.
• Demonstrated that increasing configurational entropy enhances chemical stability against CO2.
• Maintained significant proton conductivity even with increased elemental complexity.

Conclusions:

• The study introduces a new class of multicomponent, high configurational entropy oxide systems.
• Findings show a positive correlation between configurational entropy and CO2 stability in these oxides.
• This work broadens the scope of multicomponent oxide design for advanced material applications.